Managing Girdling Tree Roots

The cause of tree problems we notice above ground often lies beneath the soil.

A flattened crown on a Norway maple, early fall color and smaller than normal leaves may indicate girdling roots. These are roots that circle the tree trunk. As the tree trunk and root expand over time the root presses against the trunk and interferes with movement of water and nutrients between the roots and the leaves.

These roots can also cause one side of the tree trunk to flatten out and are more common in deeply planted trees.

Arborists use air excavation tools to expose the roots and uncover the cause of these symptoms. Girdling roots can occur at, slightly below or several inches below the soil surface.

Skilled arborists carefully remove the offending roots. Once resolved, the soil is replaced, tree is mulched, watered and monitored.

A bit more information: Nursery, planting, soil obstructions and other unknown factors can result in girdling roots. Loosen circling roots at planting to reduce the risk of these roots continuing to encircle the rootball and eventually girdle the trunk. Plant trees with the root flare (point where roots flare away from the trunk) at or slightly above the soil surface. Dig wide shallow holes and roughen the sides to encourage roots to explore the soil beyond the planting hole.